We present a thermodynamic and cost analysis of synthesis gas (syngas) production by the Zn/ZnO solar thermochemical fuel production cycle. A mass, energy, and entropy balance over each step of the Zn/ZnO syngas production cycle is presented. The production of CO and H2 is considered simultaneously across the range of possible stoichiometric combinations, and the effects of irreversibilities due to both recombination in the quenching process following dissociation of ZnO and incomplete conversion in the fuel production step are explored. In the cost analysis, continuous functions for each cost component are presented, allowing estimated costs of syngas fuel produced at plants between 50 and 500 MWth. For a solar concentration ratio of 10,000, a dissociation temperature of 2300 K, and a CO fraction in the syngas of 1/3, the maximum cycle efficiency is 39% for an ideal case in which there is no recombination in the quencher, complete conversion in the oxidizer, and maximum heat recovery. In a 100 MWth plant, the cost to produce syngas would be $0.025/MJ for this ideal case. The effect of heat recuperation, recombination in the quencher, and incomplete conversion on efficiency and cost are explored. The effects of plant size and feedstock costs on the cost of solar syngas are also explored. The results underscore the importance improving quencher and oxidizer processes to reduce costs. However, even assuming the ideal case, the predicted cost of solar syngas is 5.5 times more expensive than natural gas on an energy basis. The process will therefore require incentive policies that support early implementation in order to become economically competitive.

References

References
1.
Wilhelm
,
D.
,
Simbeck
,
D.
,
Karp
,
A.
, and
Dickenson
,
R.
,
2001
, “
Syngas Production for Gas-to-Liquid Applications: Technologies, Issues and Outlook
,”
Fuel Process. Technol.
,
71
(1–3), pp.
139
148
.10.1016/S0378-3820(01)00140-0
2.
Steinfeld
,
A.
,
2002
, “
Solar Hydrogen Production via a Two-Step Water-Splitting Thermochemical Cycle Based on Zn-Zno Redox Reactions
,”
Int. J. Hydrogen Energy
,
27
(6), pp.
611
619
.10.1016/S0360-3199(01)00177-X
3.
Venstrom
,
L.
, and
Davidson
,
J. H.
,
2011
, “
Splitting Water and Carbon Dioxide via the Heterogeneous Oxidation of Zinc Vapor: Thermodynamic Considerations
,”
ASME J. Sol. Energy Eng.
,
133
(1), p.
011017
.10.1115/1.4003417
4.
Loutzenhiser
,
P. G.
, and
Steinfeld
,
A.
,
2011
, “
Solar Syngas Production From Co2 and H2O in a Two-Step Thermochemical Cycle via zn/zno Redox Reactions: Thermochemical Cycle Analysis
,”
Int. J. Hydrogen Energy
,
36
(19), pp.
12141
12147
.10.1016/j.ijhydene.2011.06.128
5.
Charvin
,
P.
,
Abanades
,
S.
,
Lemont
,
F.
, and
Flamant
,
G.
,
2008
, “
Analysis of Solar Chemical Processes for Hydrogen Production From Water Splitting Thermochemical Cycles
,”
Energy Convers. Manage.
,
49
(6), pp.
1547
1556
.10.1016/j.enconman.2007.12.011
6.
Kromer
,
M.
,
Roth
,
K.
,
Takata
,
R.
, and
Chin
,
P.
,
2011
, “
Support for Cost Analyses on Solar-Driven High Temperature Thermochemical Water-Splitting Cycles
,” TIAX, LLC, Report No. #D0535.
7.
Bale
,
C. W.
, “
Fact Thermochemical Database
,” http://www.crct.polymtl.ca/fact/
8.
Loutzenhiser
,
P. G.
,
Barthel
,
F.
,
Stamatiou
,
A.
, and
Steinfeld
,
A.
,
2011
, “
Co2 Reduction With Zn Particles in a Packed-Bed Reactor
,”
AIChE J.
,
57
(9), pp.
2529
2534
.10.1002/aic.12460
9.
Sargent, and Lundy,
2003
, “
Assessment of Parabolic Trough and Power Tower Solar Technology Cost and Performance Forecasts
,” National Renewable Energy Lab, Report No. NREL/SR-550-34440.
10.
Kolb
,
G. J.
,
Jones
,
S. A.
,
Donnelley
,
M. W.
,
Gorman
,
D.
,
Thomas
,
R.
,
Davenport
,
R.
, and
Lumia
,
R.
,
2007
, “
Heliostat Cost Reduction Study
,” Sandia National Laboratories, Technical Report No. SAND2007-3293.
11.
Kraupl
,
S.
, and
Wieckert
,
C.
,
2007
, “
Economic Evaluation of the Solar Carbothermic Reduction of Zno by Using a Single Sensitivity Analysis and a Monte-Carlo Risk Analysis
,”
Energy
,
32
, pp.
1134
1147
.
12.
2013. Coyote Lakes Road, Yermo, CA 92398: 640 Acres, for Commercial Use, With Water and Electricity. Real Estate Listing, July, www.zillow.com
13.
Kistler
,
B.
,
1986
, “
A User's Manual for DELSOL3: A Computer Code for Calculating the Optical Performance and Optimal System Design for Solar Thermal Central Receiver Plants
,” Sandia National Laboratories, Sandia Report No. SAND86-8018.
14.
Weimer
,
A.
,
Perkins
,
C.
,
Lichty
,
P.
,
Funke
,
H.
,
Zartman
,
J.
, and
Hirsch
,
D.
,
2009
, “
Development of a Solar-Thermal Zno/Zn Water-Splitting Thermochemical Cycle
,” University of Colorado and NREL, Final Report to NREL (DE-PS36-03GO93007-Subcontract-05-SHGR-006).
15.
Turchi
,
C.
, and
Heath
,
G.
,
2013
, “
Molten Salt Power Tower Cost Model for the System Advisor Model (SAM)
,” NREL, Technical Report No. NREL/TP-5500-57625.
16.
Peters
,
M.
,
Timmerhaus
,
K.
, and
Ronald
,
W.
,
2003
,
Plant Design and Economics for Chemical Engineers
,
5th ed.
,
McGraw-Hill Education
, New York.
17.
Tribe
,
M. A.
, and
Alpine
,
R. L. W.
,
1986
, “
Scale Economies and the “0.6 rule”
,”
Eng. Costs Prod. Econ.
10
(
4
), pp.
271
278
.10.1016/0167-188X(86)90053-4
18.
Vogel
,
W.
, and
Kalb
,
H.
,
2010
,
Large-Scale Solar Thermal Power
,
Wiley-VCH
, Weinheim, Germany.
19.
Gstoehl
,
D.
,
Brambilla
,
A.
,
Schunk
,
L. O.
, and
Steinfeld
,
A.
,
2008
, “
A Quenching Apparatus for the Gaseous Products of the Solar Thermal Dissociation of zno
,”
J. Mater. Sci.
,
43
(14), pp.
4729
4736
.10.1007/s10853-007-2351-x
20.
Murphy
,
R.
, and
Jaccard
,
M.
,
2011
, “
Modeling Efficiency Standards and a Carbon Tax: Simulations for the US Using a Hybrid Approach
,”
Energy J.
,
32
(1), pp.
37
54
.
21.
Nicodemus
,
J. H.
, and
McGuinness
,
M.
,
2014
, “
Carbon-Neutral Solar Syngas: Cost and Policy Considerations
,”
Proceedings of the American Solar Energy Society Solar 2014 Conference, San Francisco, CA, July 6–10
.
22.
Brown
,
F. L.
,
2008
, “
The Evolution of Markets for Water Rights and Bulk Water
,” New Mexico Water Resources Research Institute.
23.
Walton
,
B.
,
2010
, “
The Price of Water: A Comparison of Water Rates, Usage in 30 U.S. Cities
,”
http://
www.circleofblue.org/waternews/2010/world/the-price-of-water-a-comparison-of-water-rates-usage-in-30-u-s-cities/
24.
Rubin
,
E. S.
,
2001
,
Introduction to Engineering and the Environment
,
McGraw-Hill
, Boston.
25.
Haltiwanger
,
J. F.
,
Davidson
,
J. H.
, and
Wilson
,
E. J.
,
2010
, “
Renewable Hydrogen From the Zn/Zno Solar Thermochemical Cycle: A Cost and Policy Analysis
,”
ASME J. Sol. Energy Eng.
,
132
(4), p.
041011
.10.1115/1.4002511
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